It is known that liquefied gas for domestic use, in particular for supply to cookers and possibly heating appliances, is distributed to the users by means of refillable pressurized cylinders, which have considerable weight and bulk, from service centres which also effect the collection of the exhausted cylinders and the refilling thereof.
The costs of delivery have a significant effect on the service, the timing of which is generally difficult to match to requirements, which can therefore be met only by providing, on the premises of the user, a reserve cylinder to replace the exhausted cylinder as soon as the need therefor arises.
The domestic storage of the reserve cylinder and the installation thereof for use, which installation is carried out by generally inexpert persons, constitute a non-negligible risk factor, which is aggravated by the difficulty of having to handle an object which is bulky and of considerable weight.
It is also known that in order to ensure greater safety, improved portability and convenience of use, the liquefied gas may be supplied in single-use sealed cartridges (or even cartridges having a closing, non refill valve) of restricted dimensions and limited capacity, of the order of one liter or less, which, when exhausted, are discarded.
By virtue of the ease of handling of these cartridges and of the reduced bulk of the appliances which make use of them, these cartridges find widespread use for camping and for supplying portable appliances in which the limited independence and heating power which can be provided by the cartridges do not constitute a problem, as is, however, the case in domestic use, where it is obligatory to employ refillable cylinders of greater capacity, with the disadvantages which have already been indicated.
It has been proposed, to overcome the limited autonomy of the cartridges, to provide a manifold set which houses a valve-type-cartilage battery and which can be operated to control the joint opening of the valve of all the cartridges installed in the set, thus connecting them jointly to a delivery pipe.
An example in this direction is provided by the document FR-A-2.642.142.
The proposed solution does not ensure the service continuity and from the user standpoint does not provide adequate safety.
In fact, if due to inadvertency, even a single one of the cartridges which must be installed in the manifold set is not installed, or is improperly set, very dangerous gas leakage can occurr.
In addition replacement of the exausted cartridges can only be performed collectively and requires the manifold set to be put out of service.
Further the use of a number of cartridges lesser than the number of cartridges to be installed is impossible and therefore it is not possible to tailor the equipment to different user needs.
Similar limitations are present in U.S. Pat. No. 3,161,322 which discloses a pocket gas dispenser where a plurality of micro cartidges can be selectively connected to a manifold, through a compressible pad operating as a shut-off valve when compressed.
Depending on the compression degree imposed by axial movement of the cartridge against the pad, a cartridge can be punctured by a pin, the pad then intercepting communication of the cartridge with the manifold, then, moving the cartridge away from the pin, the pad compression is released and the communication is established.
Although collective connection of several cartridges to the manifold or selective exclusion therefrom can be provided, it is not possible to perform a selective replacement of the cartridges, by the more with the dispenser in use, nor to load the dispenser with a number of cartridges lesser than the one for which it is designed, because that would involve gas leakage.
Control of the connection opening or shut-off requires further a displacement of the cartridges, easily achievable with micro cartridges only.
FR-A-2.076.256 discloses a cabinet and gas cylinders contained therein; the gas cylinders are connected to a common manifold, each cylinder through a respective pressure reducer and a respective shut-off tap.
The present invention aims to provide a manifold/distributor for combustible gas supplied from a plurality of liquefied-gas cartridges, which manifold/distributor is capable of performing as well as a refillable cylinder while in addition giving continuity of service, safety of use and ease of replacement of the cartridges, when exhausted, the supplying of which is particularly convenient, and can be carried out directly by the user, without the need to have recourse to a service centre.
These results are achieved, according to the present invention, by a manifold/distributor assembly comprising a frame forming a plurality of cartridge housings, at least partial housings, and a manifold provided with a plurality of valve assemblies each incorporating an actuation element for opening the cartridges, one for each cartridge housing, which valve assemblies are normally closed and are only opened when a cartridge is present in the respective housing, characterized by comprising a multiple-way tap, which puts a delivery conduit in fluid communication with the whole manifold, with portions thereof or with none of them.
The manifold/distributor can be provided with a pressure-reducing regulator, which is conventional per se, with outlet adapter for connection to a consumer appliance,. for example a domestic cooker.
The cartridges are preferably of the valve-type with screwed boss for cartridge mounting, of the standard type defined for instance by European Regulation EN 417, but with a modified bottom which enables their manual holding and their screwing even in case a plurality of cartridges is tightly juxtaposed.
Preferably the valve assemblies provide a double closing protection and consist in a shut-off valve, opened only in presence of a cartridge, coupled to the cartridge shut-off valve, and in a non return valve, cascade connected.
According to a further aspect of the present invention, the frame forms a container for the manifold and the cartridges which can be tightly closed for transportation or storing in very safe conditions.
Advantageosly the tight container can be provided, for further safety, with a pressure detection device for detecting internal overpressure of the container resulting from gas leakage and for signalling the event.
A vent pipe may also be provided to put the container in communication with the external ambient, so as to prevent local and indoor formation of inflammable gas mixture in case of gas leakage.